Method and apparatus for earth grading and allied arts



June 2 1957 D. LLBENSINGER 2,796,685

METHOD AND APPARATUS FOR EARTH GRADING AND ALLIED ARTS Filed Dec. 15,1951 3 Sheets-Sheet l I N V EN TOR. flaw/4L0 Z- Jen/swam M. 714% Eng;

ATTORNE 5 June 25, 1957 D. L. BENSINGER 2,796,685

METHOD AND APPARATUS FOR EARTH GRADING AND ALLIED ARTS Filed Dec. 15,1951 5 Sheets-Sheet 2' INVENTOR. flaw/aw!- Jews/N65? June 25, 1957 D.1.. BENSINGER 2,795,685

METHOD AND APPARATUS FOR EARTH GRADING AND ALLIED ARTS Fi led Dec. 15,1951 5 Sheets-Sheet 3 fie 3 1N VEN TOR. I

00mm 1. BFIVS/IYGER METHOD AND APPARATUS FDR EARTH GRADENG AND ALLEEDARTS Donald L. Bensinger, Hastings, Mich; Isahell McK. Bensinger,administratrix of said Donald L. Bensinger, deceased, assignor toherself Application December 15, 1951, Serial N 0. 261,886

10 Claims. (Cl. 37143) The present invention relates to methods andapparatus for earth working including grading and allied operations.

One of the principal objects of the invention is the provision of anovel and improved method of and apparatus for working earth to adesired surface, which utilizes as a basic information source areference plane,- such as a plane established by a radiated or otherwisepropagated plane of energy or a plane of energy established by anabsolute reference elevation device, to control the elevation of anearth moving or cutting instrumentality during moving of theinstrumentality in an appropriate manner relative to an earth surface,as for instance, in a direction generally parallel with the referenceplane. Whenever the term or expression energy is employed herein it is mant to include not only radiated or propagated energy but also energyderived from barometric forces or gravitational forces.

Another of the principal objects of the invention is the provision of anovel and improved method and apparatus of the character referred toincluding the use of memory and/or programmed information in the controlof the earth moving instrumentality.

Another of the principal objects of the invention is the provision of anovel and improved method of and apparatus for elevation surveying whichutilizes information sources of the character referred to above.

Further objects and advantages of the invention will be apparent tothose skilled in the art to which it relates from the followingdescription of the preferred embodi-- ments of the invention describedwith reference to the A accompanying drawings forming a part of thisspecification and in which similar reference characters desig natecorresponding parts throughout the several views.

Fig. 1 is a perspective vi w of an earth grading operation utilizin thepresent invention;

Fig. 2 is an enlarged view of the earth moving apparatus shown in Fig.1; and

Fig. 3 is a diagrammatic view of a representative control mechanismemployed.

in applying the invention to earth grading, an earth movinginstrumentality is moved by power means in a direction generallyparallel with a reference plane of. energy which may be establishedeither by a plane of energy, such as electromagnetic, supersonic orother forms of propagated or radiated energy or by an absolute referenceelevation apparatus, such as a device responsive to slight changes ingravitational force or barometric pressure, and the position of theearth moving or cutting instrumentality or element relative to thereference plane controlled either manually or automatically byinformation derived from the propagated en-- ergy or absolute referenceelevation device. The earth moving instmmentality may be of any suitablecharacter and may be carried by, attached to, or form a part of asuitable vehicle or the like by virtue of which it may be moved in anapproproate manner over the surface to be graded, etc.

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For purposes of illustration, there is herein shown and described apreferred embodiment of theinvention especially adapted for grading anearth area; for example, a field A, such as an air field or a field tobe irrigated, to a desired plane surface by use of a radiated plane ofelectromagnetic energy. An omni-directional antenna B connected to asuitable transmitter C transmits electromagnetic energy equally in alldirections in a confined, generally horizontal plane parallel to theplane to which the field A is to be graded. The transmitter C mightcomprise conventional short wave or infra-red transmission equipment andis provided with a suitable power source, not shown. The antenna B maybe located in or to one side of the field A, as desired, and thereference plane of energy, designated generally as D, is established bymechanically positioning the transmitting antenna B to bear a known,fixed, dimensional relation to the plane to which the field A is to begraded by the earth grading apparatus. The antenna B is located remotefrom the earth grading apparatus which, as shown, comprises a vehicle Eincluding an active earth moving instrumentality or element in the formof an elongated scraper or cutter blade F. A tractor G is shown formoving the vehicle E about the field A. The position of the lower activeedge 10 of the blade F relative to the reference plane D is controlledby deviation of receiving antennas or sensing units H, H from the energyreference plane D.

The vehicle E shown comprises an elongated, box-like body 11 supportedfor movement about the field A by a plurality of front and rear wheels12, 13, respectively, and is adapted to move about the field A to begraded in a conventional manner by the tractor G which may be ofconventional construction. Opposite ends of the scraper or cutting bladeF are connected to and carried by the lower ends of a pair of connectingrods 16 of similarly constructed, vertically positioned, doubleacting,reciprocating type fluid pressure operated motors J, the cylinders 17 ofwhich are fixed to opposite sides of the vehicle body 11. Suitablebearing brackets also connected to opposite sides of the body 11 assistin guiding the connecting rods 16 which move in a generally verticaldirection. From the foregoing, it will be apparent that opposite ends ofthe blade F can be independently moved with respect to the body 11 ofthe vehicle E by control of the flower" fluid pressure to and fromopposite ends of the cylinders 17 of the motors J at opposite sides ofthe vehicle.

The detectors orsensing units H; H are located above the velL'cle properand are mechanically connected to opposite ends of the earth :movingblade P so that they always occupy the same relative position withrespect to the lower, active edge 10 of the blade F. As shown, the

sensing units H, H are connected to the upper ends of rods 20, 29', thelower ends of which are connected to the bladeF. The rods 20, 29' areconnecte'dto opposite sides'of the body 11 of the vehicle E by suitableguide brackets for movement parallel with the movement of the connectingrods 16. The connections between the sensing units H, H and oppositeends of the blade 16 are preferably such that the relative distancetherebetween can be adjusted, if desired. 7

The electromagnetic energy detectors or sensing units H, H may be of anysuitable type. Those shown are of the bolometer type; that is, theirresistance changes with the amount of electromagnetic energy to whichthey are exposed. Each sensing unit comprises two vertically spaced,sensitive areas 21, 22 and 21', 22 essentially cylindrical in shape soas to be equally sensitive to incident radiation from all directions.The combined sensitive areas of each detector unit is greater invertical dimension than the width of the radiated plane of en- I motor Iat the far side of the vehicle bythe sensing unit- H. Since the controlfor both motors is the same, only the control for the motor I on thenear side of the vehicle will be described in detail. Wherecorresponding parts of (the control for the motor I on the'other side ofthe vehicle appear in the drawings, they are designated by the samereference character with a prime markiaffixed thereto.

The two sensing areas 21, 22 of the detector unit H are arranged to'formtwo active arms of a normally balanced Wheatstone bridge circuit,designated generally as M. When both sensing areas 21, 22 are equallyilluminated by the radiation from the antenna B, the resistance of eacharea is the same and the bridge circuit remains in balance with nosignal being transmitted to the amplifier 25. This condition correspondsto the desired dimensional relation between the reference datum plane Destablished by the omni-directional radiated energy and .the lower orcutting edge It) of'the active earth-moving element or blade F.

If the position of the cutting blade F is such that the midpoint of thedetecting or sensing units H does not coincide with the plane D ofradiated energy, then the two sensing surfaces 21, 22 thereof will beunequally illuminated and hence the bridge associated therewith will beunbalanced. The bridge is supplied with energy from a bridge supplycircuit 23 which may be connected to the power supply 24 from a suitablegenerator on the tractor G. Any bridge unbalance signal is applied to anamplifier 25 and the output of the amplifier applied to one phase of atwo-phase induction motor P. The second phase of the two-phase inductionmotor P may be connected to the bridge supply 23. The difference in theillumination of the two sensing areas 21, 22 will determine theamplitude and polarity of bridge unbalance and hence cause a signal tobe generated which will be related to whether the particular end of theblade F connected thereto is too high or too low. The polarity of bridgeunbalance determines the direction of rotation of the two-phase motor P.The magnitude of unbalance determines the angular rotation andcontributes to the initial torque of the motor P in its bladepositioning action.

The motor P is connected to a dilferential-type pressure valve R whichcontrols the flow of pressurized fluid to opposite ends of the cylinder17 of the motor I and maintains equal pressure on opposite sides of thepiston of the motor. As the valve R is moved, the end of the blade F towhich the motor I is connected is caused to be moved up or down, as thecase may be. Pressurized fluid may be supplied to the valve R from apump on the.

tractor G by supply and return lines 26, 27, respectively. The motion ofthe blade F tends to restore the mid-point of the sensing unit H to thereference datum plane established by theradiated energy. Theconstruction is such that deviation of the detector H from the referenceplane supplies a signal which then acts to re-position the detectorrelative to the plane of the reference wave and, in turn, the blade F apredetermined distance therefrom.

The use of two detector or sensing units H, H connected to opposite endsof the earth moving element in the manner shown constitutes one specificform of automatic compensator for vehicle attitude; that is, anyrotation or movement of the vehicle about its own axes, and maintainsthe active edge of the blade F always parallel with the reference planeD or at a desired predetermined angle thereto. Alternatively a singledetector or sensing unit may be employed to determine the position ofthe blade F with respect to the reference plane or the general plane ofthe vehicle and a suitable device employed to maintain the blade F levelor in the desired angular position with respect to the reference plane.

The vehicle E shown comprises an elevator conveyor 28, the lower end ofwhich is disposed adjacent to and connected to one end of the blade F.The upper end of the elevator conveyor 28 is connected to the body 11 bya link 29 which permits vertical movement of the conveyor and dischargesinto the rear end of the body 11 of the 'vehicle. The construction issuch that excess earth accumulated in front of the blade F istransferred by the elevator 28 to the vehicle body. Provision is alsomade for supplying earth ahead of the blade F in the event there is adepression in the field being graded. For this pumose the front end ofthe body 11 is open as at 30 and the body 11 behind the opening 30supplied with a conveyor 31 adapted to discharge earth deposited thereonas by the elevator conveyor 28 ahead of a scraper blade 32 located infront of and slightly above the level of the blade F. The conveyor 31may be intermittently actuated, as required, to discharge earth from thebody of the vehicle ahead of the blade 32 which spreads the same. Amechanical tamper or roller, designated generally as T, may be employedbetween the blades F and 32 if it is desired to tamp or compact theearth ahead of the blade F. 'The blade 32 includes manually operatedmeans which may be provided for adjusting the blade vertically; however,it is preferably moved automatically in relation to the blade F. Thiscan be accomplished, for example, by connecting the blade to a pair ofpressure motors U similar to the motors J and connecting the motors U inparallel circuit with the motors J.

Obviously there is a maximum out which the blade F is capable of taking,considering the character of the vehicle E, the power of the tractor G,the kind of earth encountered, and some suitable stop means is providedfor limiting the maximum depth to which the blade F can be moved. If thecontrol system is functioning properly, the blade F is maintained at'alltimes in its desired position relative to the reference plane ofelectromagnetic energy and the bridge output is zero. If, however, thecut required at any particular instance is greater than the greatest outwhich the blade F is capable of making, a continuous bridge outputsignal will exist.

This signal can be transmitted over a radio link by conventionaltransmission equipment, not shown, but includes the antenna V to aremote unit; for example, a self-tracking radar unit W which has as itsfunction the recording of the position or location where further gradingmust be performed. The amount of fill required or excess dirt to beremoved can be also recorded, if desired, as this will be a function ofthe strength and polarity of the bridge unbalance signal. The desiredinformation can be recorded in graphic form, or the like, andconstitutes a memory of performance which can form the basis forsubsequent direction, etc., of the earth moving vehicle.

As an alternative construction, the sensing units H, H could be replacedby absolute reference elevation devices; for example, gravity responsiveor barometric pressure operated devices and the location of the blade Frelative to the datum plane established thereby determined in a similarmanner. In this event, the earth moving vehicle, as such, could remainthe same as may the earth moving or cutter blade and its hydraulicpositioning mechanism, the valve and valve operating motors, and theamplifiers for driving them. The radiation sensitive sensing units wouldnot be required and the sensing bridge WOllld'bB different. with energyand yield an output signal in the same manner as the bridge alreadydescribed. Y

Two arms of the new bridge, constituting the ratio arms, can beconventional, variable resistors and, the other two arms may consist ofelectrical wire resistance The new bridge, however, may be supplied:

strain gauges. One of the strain gauges can be 'afi'ixed to an absolutebarometric pressure pick-up or device. The other of the strain gaugesmay serve as a dummy to compensate for ambient temperature changes, etc.The barometric element may consist of an evacuated chamber connectedthrough a flexible bellows arrangement to a rigid member such thatvariations in atmospheric pressure would cause the rigid member toundergo a linear displacement. The electrical Wire resistant straingauge forming the active bridge arm would monitor the motion of thismember. Movement of the member would change the resistance of the straingauge and hence unbalance the bridge. The barometric element would beoperatively connected to the cutting blade and changes in height thereofwould cause changes in pressure which, in turn, would vary theresistance of the strain gauge forming the active bridge arm andactivate the hydraulic motors to re-establish the cutting blade at thepredetermined desired height or elevation.

Two barometric sensitive devices, etc., can be employed, one connectedto each end of the blade, and automatic compensation for vehicleattitude thus obtained in a manner similar to the manner in which it isobtained by the use of the two sensing units H, H, etc., of thepreferred embodiment.

In operation, the bridge or bridges, as the case may be, can be balancedmanually by means of the adjustable bridge ratio arm resistances, withthe cutting blade at the desired predetermined height or elevation andthe vehicle thereafter moved about the field to be graded. Any deviationof the blade or either end thereof, as the case may be, up or down fromthe elevation established, will result in a change in pressure on thebarometric element connected thereto which, in turn, will change theresistance of the active bridge arm associated therewith, therebycausing the bridge to produce an output signal which will, in turn,activate the automatic positioning mechanism to re-position the blade toits original prededetermined elevation.

Variations in pressure, due to changing atmospheric conditions at anygiven time, may be compensated for by varying the resistance of one ofthe ratio arms of the bridge from a remote location via a radio linkover which a control signal is transmitted to the vehicle, which sig*nal is a function of the atmospheric pressure existing at a stationarypoint corresponding with the reference level or plane. This atmosphericpressure may be detected by a barometric pressure sensitive elementsimilar to that referred to above. Variation of this stationarybarometric pressure element can modulate a radio transmitter which wouldtransmit a signal to the vehicle, which signal would act upon one of thebridge ratio arms so as to compensate for the variation in atmosphericpressure due to atmospheric phenomena.

Programmed type information can be incorporated into the system bysending a control signal to the vehicle via a radio link so as to varythe resistance of the ratio arm of the bridge in accordance with theprescribed predetermined program which may be correlated with positioninformation of the type yielded by the remote radar tracking unitpreviously referred to.

While a specific type of earth moving apparatus is illustrated, anysuitable earth moving mechanism may be employed; for example, a ditchingmachine. If the field, ditch, etc., is to have a desired inclination orslope, as would be the case in leveling a field to be irrigated ordigging a ditch for a drainage system, the plane of the radiated energycan be inclined to the desired angle or provision can be made formanually or automatically changing, in a desired manner, the elevationof the reference plane by changing the physical position of theradiating antenna or the relative position between the earth movinginstrumentality and the sensing units or the physical position of theabsolute reference elevation devices, referring to the alternativearrangement described,

with respect to the earth moving instrumentality, or the physicalposition of the so-called stationary, compensating, barometric pressureelement if such is employed. For example, the range and angular positionof the earth moving vehicle can be displayed at the remote radartracking unit W on a cathode-ray tube in a manner known as a planposition indicator and photo-electric cells located above the planposition indicator so as to be illuminated by light from the spotappearing on the plan position indicator, said spot indicating theinstantaneous position of the earth moving vehicle. As the variousphotoelectric cells are successively illuminated, electric signals canbe generated and employed to control hydraulic or other mechanism forchanging the physical position of the radiating antenna, etc., inaccordance with any desired predetermined program.

As previously mentioned, the equipment referred to can be used to takelevels. To do this, a sensing unit similar to one of the units referredto can be fixedly connected to a vehicle and the vehicle driven over thedesired surface with a mechanism connected to the output of the bridgecircuit for recording the amplitude and polarity of the signal receivedtherefrom. This signal will be a function of the deviation of thesensing unit from the reference plane and hence the record obtained willbe an indication or record of the ground contour. The bridge signal maybe recorded on the vehicle and/ or be transmitted to the self-trackingradar unit for recording.

From the foregoing, it will be apparent that the objects of theinvention heretofore enumerated and others have been accomplished andthat there has been provided a novel and improved method of andapparatus for grading, surveying, etc. While preferred embodiments ofthe invention have been described in considerable detail, the inventionis not limited to the apparatus shown and described. Numerous changescan be made therein as will be apparent to those skilled in the art towhich the invention relates; for example, the signals obtained from thebridge circuits disclosed and which are, in the preferred embodimentdescribed, used to automatically control the position of the earthmoving instrumentality with respect to the reference or datum plane,could be used to actuate a visible indicator, which visible indicationcould, in turn, be employed by an operator to manually control theposition of the earth moving instrumentality.

While two embodiments including two different sensing systems have beendescribed in considerable detail, other embodiments are contemplated,such as systems employing, for example, infra-red radiation,phase-difference sensing and/or reflected energy and it is my intentionto cover hereby all adaptations, modifications and uses of my invention.

Having thus described my invention, I claim:

1. The method of working earth which comprises establishing a referenceplane of energy and utilizing said energy plane to control the positionof an earth moving instrumentality relative thereto while moving saidinstrumentality in a direction generally parallel to said plane ofenergy.

2. The method of working earth which comprises radiating a plane ofenergy and utilizing said energy to control the position of an earthmoving instrumentality relative thereto while moving saidinstrumentality in a.

direction generally parallel to said plane of energy.

3. In an earth working apparatus, a movable vehicle, an earth movinginstrumentality carried by said vehicle for movement relative thereto,means for establishing a reference or datum plane of energy, and meansresponsive to deviation of the earth working apparatus from saidreference plane for controlling the position of said instrumentalityrelative to said reference plane.

4. In an earth working apparatus, a movable vehicle having a frame, anearth moving instrumentality carried by said vehicle for movementrelative to said frame,

power-actuated means for moving said earth moving instrurnentalityrelative to said frame, means for establishing a reference or datumplane of energy, and means responsive" to deviation of the earth workingapparatus from said datum or reference plane for automaticallycontrolling said power-actuated means to maintain said instrumentalityin predetermined position relative to said reference plane.

1 5. In an earth Working apparatus, a movable vehicle, an earth movinginstrumentality carried by said vehicle for movement relative thereto,means remote from said vehicle for transmitting a plane of energy, andmeans on said vehicle for utilizing said energy to control the positionof said earth moving instrumentality relative to said plane of energy.

6. In an earth working apparatus, a movable vehicle having a frame, anearth moving instrumentality carried by said vehicle for movementrelative to said frame, power-actuated means for moving said earthmoving instrumentality relative to said frame, means remote from saidvehicle for transmitting a plane of energy, and means on said vehiclefor utilizing said energy to automatically control said power-actuatedmeans to maintain said earth moving instrumentality in predeterminedposition relative to said plane of energy.

7. In an earth grading apparatus, a movable vehicle, an earth movinginstrumentality carried by said vehicle for movement relative thereto,means for establishing a reference or datum plane of energy, means fordetecting deviation of the earth grading apparatus from said referenceor datum plane, and means for utilizing said lastnamed means to controlthe position of said earth moving element relative to said reference ordatum plane.

8. In an earth working apparatus, a movable vehicle including a frame,an earth moving instrumentality carried by said vehicle for movementrelative to said frame,

9; In an earth grading apparatus, a movable vehicle including a frame,an earth moving instrumentality carried by said vehicle for movementrelative to said frame, power actuated means for moving said earthmoving instrumentalityrelative to said frame, means for establishing areference or datum plane of energy, meanson said vehicle responsive todeviation of the earth grading apparatus from said datum plane, andmeans controlled by said deviationresponsive means for automaticallycontrolling actuation of said power-actuated means to maintain saidearth moving instrumentality in predetermined relative position to saidreference plane.

10. In an earth grading apparatus, a movable vehicle including a frame,an earth moving instrumentality carried by said vehicle for movementrelative'to said frame,

power-actuated means for moving said earth moving instrumentalityrelative to said frame, means remote from said vehicle for establishinga radiant energy reference or datum plane, means on said vehicleresponsive to de- References Cited in the file of this patent UNITEDSTATES PATENTS OTHER REFERENCES American Civil Engineers Handbook, fifthed. Published by John Wiley and Sons, New York, 1930, pages 460-463. r

